Browsing by Author "Barragan, Blanca E"
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- A biorefinery from Nannochloropsis sp. microalga – Extraction of oils and pigments. Production of biohydrogen from the leftover biomassPublication . Nobre, B. P.; Villalobos, Fidel; Barragan, Blanca E; Oliveira, Ana Cristina; Batista, Ana Paula; Marques, Paula; Mendes, Rui L.; Sovová, H.; Palavra, António F.; Gouveia, LuisaThe microalga Nannochloropsis sp. was used in this study, in a biorefinery context, as biomass feedstock for the production of fatty acids for biodiesel, biohydrogen and high added-value compounds. The microalgal biomass, which has a high lipid and pigment content (mainly carotenoids), was submitted to supercritical CO2 extraction. The temperature, pressure and solvent flow-rate were evaluated to check their effect on the extraction yield. The best operational conditions to extract 33 glipids/100 gdry biomass were found to be at 40 °C, 300 bar and a CO2 flow-rate of 0.62 g/min. The effect of adding a co-solvent (ethanol) was also studied. When supercritical CO2 doped with 20% (w/w) ethanol was used, it was possible to extract 45 glipids/100 gdry biomass of lipids and recover 70% of the pigments. Furthermore, the remaining biomass after extraction was effectively used as feedstock to produce biohydrogen through dark fermentation by Enterobacter aerogenes resulting in a hydrogen production yield of 60.6 mL/gdry biomass.
- Exploring Scenedesmus obliquus and nannochloropsis sp. potential as a sustianable raw material for biofuels amd high added value compoundsPublication . Gouveia, Luisa; Batista, Ana Paula; Nobre, B. P.; Marques, Paula; Moura, Patrícia; Alves, Luís; Passarinho, Paula; Oliveira, Ana Cristina; Villalobos, Fidel; Barragan, Blanca E; Palavra, António F.In this work, the authors propose a microalga-based integrated system, where optimization of several energy vectors (biodiesel, bioethanol and bioH2) is highlighted under the concept of biorefinery (Project PTDC/AAC-AMB/100354/2008). This involves the integration of different processes such as oil and sugar extraction from microalgae for biodiesel and bioethanol production respectively, and bioH2 production from the whole and/or biomass leftovers. The extraction of high value added compounds, such as carotenoids, contributes to the economic viability of the overall process.